Study of imbibition in seeds/raisins

Aim Of The Experiment

To study and demonstrate the amount of water that is imbibed by raisins.

Theory

What is imbibition?

It is the phenomena wherein water adsorption takes place by substances without solution formation. Example: When seeds are immersed in water, they swell due to imbibition. This swelling up causes a temporary increase in the volume of the cell and does not require energy as materials are transported passively.

Raisins increase in size due to imbibition of water. The quantity of water imbibed can be obtained by considering the difference in the mass between the dry raisins and the swollen raisins.

How is water transported to different parts of the plants?

It is transported through imbibition, diffusion, and osmosis.

What are imbibants and adsorbents?

They are the substances that imbibe water. Example of imbibants – Starch. The adsorbent is the liquid that is imbibed.

Why does Imbibition occur?

It primarily occurs due to the presence of lyophilic and hydrophilic colloids. Through the sub-microscopic capillaries that are located on the body’s surface water is imbibed.

The imbibition of water continues until a dynamic equilibrium is established which causes an increase in the imbibant’s volume resulting in imbibitional pressure which is of enormous magnitude.

How is imbibition affected?

Some factors that can affect the imbibition rate are:

  • Temperature – Imbibition rate is directly affected by the temperature
  • Imbibant’s nature – Starch has lesser capacity while proteins have a great imbibing capacity.
  • Solute’s concentration – It is indirectly proportional to the rate of imbibition. Increase in the rate of imbibition is observed when the concentration of solute is less.
  • Imbibition rate is directly related to the surface area of the imbibant. The greater the surface area the more the rate of imbibition.

Significance Of Imbibition

  • Germination of seed is inducted by imbibition
  • The force generated by imbibition is required for the cohesion of water to the elements of xylem
  • Retention of water by fruits is due to imbibition
  • Ripening of ovules into seeds is due to imbibition as it causes water movement to the ovules.

Materials Required

  • 25-30 raisins with their stalks intact
  • Blotting paper
  • Petri dish
  • Electronic balance
  • Spatula
  • Beaker
  • Distilled water

Procedure Of The Experiment

  • Weigh around 20 raisins that are dry and with intact stalks on an electronic balance
  • Make note of the weight
  • Into the small beaker, add some distilled water
  • Shift the weighed raisins to the beaker
  • Leave the raisins soaking in water for around 2 to 3 hours
  • Once soaked, shift the raisins from the beaker to a petri dish placed with a blotting paper with the help of a spatula
  • Gently pat dry the raisins
  • Make note of the weight of the dry raisins using the electronic balance

Observations

  • Dry raisins weigh x_________ gm
  • Swollen raisins weigh y ___________ gm

Calculations

  • The water absorbed by the raisins weigh = (y – x) gm
  • The water absorbed by the raisins in percentage = «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac»«mrow»«mo»(«/mo»«mi»y«/mi»«mo»-«/mo»«mi»x«/mi»«mo»)«/mo»«/mrow»«mi»x«/mi»«/mfrac»«/math»

Precautions

Raisins that are used in the experiment should be ensured of being dry and clean and having their stalks intact.

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Further Reading

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